As the statement of the Queriest is "On which amount the Interest is Payable?", and it being an active sentence it is presumed that he has not paid interest to date on the Liability, as the question being asked is "On what amount the interest is payable".

As per GST Rules (Refer Sec 50 and clauses thereto) the Interest is to be calculated "Till the Date the Amount is not Paid" and hence accordingly the answer.

Also one question for my unders, how can one rectify the GST Return for a particular month, when the option is not itself enabled in the system?.